The invention relates to a process for dispensing a powdery product from a container with a dispensing nozzle aimed downwards, as well as to a device which can be used for this process.
Processes and devices for dispensing a powdery product are known in many embodiments. A problem when dispensing a powdery product from a container, where the product must flow from the dispensing nozzle under the effect of gravity, resides in the so-called bridge and tunnel formation due to caking in the product. This obstructs or prevents the powdery product from flowing out. Solutions to this problem can be found in JP-A-8313329, DE-A 43 29 356, U.S. Pat. No. 4,541,765 and FR-A-2 479 704. In all these publications there is question of a bag-shaped (inner) container which at the topside is suspended or supported in a movable way, where the movement at the topside of the bag-shaped (inner) container is supposed to prevent or remove the bridge and tunnel formation. All these publications relate mainly to larger containers for bulk applications.
The present invention now intends to provide a process and device for dispensing a powdery product which are very effective in the prevention of bridge or tunnel formation and which are also suitable for use with smaller containers.
To this end the process according to the invention is characterised in that a flexible part of the container is deformed at least near the dispensing nozzle, preferably by means of movement in a direction with a component at a right angle to the dispensing nozzle. By deforming a flexible part of the container at least near the dispensing nozzle, the problem is attacked at the root, i.e. a deformation is caused at the location where the bridge or tunnel formation occurs, so that this bridge or tunnel is disturbed due to deformation of the adjacent part of the container. The container is preferably moved relative to the dispensing nozzle and such a movement can be achieved easily, for instance by tilting the container around a tilting shaft which is approximately horizontal.
If the movement of the container and the dispensing of a measured quantity of product from the dispensing nozzle are carried out each time immediately after one another, the bridge or tunnel formation will be avoided entirely. In the event that the container is equipped with a dispensing device, it is advantageous to let this dispensing device work by shocks. The effects of these shocks will also be felt in the container and in the powdery product contained therein, which also contributes to the prevention, or removal, of tunnel or bridge formation.
The device according to the invention which can be used with the process described above is characterised to that end in that the container is provided with a movable part at least near the dispensing nozzle, which is preferably mobile in a direction with a component at a right angle to the dispensing nozzle.
It is advantageous if the container is provided with flexible bellows adjacent to the dispensing nozzle, which bellows preferably become wider in the upward direction from the dispensing nozzle towards an essentially rigid part of the container.
By making deformable only the part of the container which is adjacent to the dispensing nozzle, the deformation caused by a movement of the container is concentrated in the area near the dispensing nozzle, so that the movement of the container is used with optimal effectiveness for the deformation, respectively disturbance, of the bridge or tunnel formation. The container can be supported in a movable, and preferably tilting, way by a support around a horizontal shaft.
In the event that the device is provided with a dispensing device for dispensing predetermined portions of the product, it is preferable to connect the dispensing device with the container by means of a transmission mechanism for converting the movement of the container into a movement of the dispensing device.
In this way a single transmission, which can also be realised manually, can achieve a double action, namely the successive deformation of the container and the activation of the dispensing device.
It is then advantageous if the transmission mechanism is equipped with a tensioning mechanism with a spring, in particular a tension spring, which is tensioned by the movement of the container and of which the tension force can be released for carrying out a movement of the movable part of the dispensing device from a filling position, in which the dispensing cavity is in line with the dispensing nozzle, to a dispensing position in which the dispensing cavity can be emptied.
In this embodiment the dispensing device is driven by the spring which is tensioned by the movement of the holder. Especially when the energy of the spring is released abruptly and therefore the movable part of the dispensing device is moved from a filling position to a dispensing position, the movable part will reach the dispensing position at a high speed and if this movement is not absorbed, the stopping of the movable part will result in a shock in the container, which contributes to the prevention, respectively removal, of the bridge formation, as already indicated above.
The process and device according to the invention are suitable in particular for being used for dispensing small portions of a powdery product, especially dispensing powder for preparing drinks, such as soup powder, coffee powder and the like.